Method, system and apparatus for image capture, analysis and transmission

ABSTRACT

A method, system and apparatus for image capture, analysis and transmission are provided. A link aggregation method involves identifying controller network ports to a source connected to the same subnetwork; producing packets associating corresponding controller network ports selected by the source CPU for substantially uniform selection; and transmitting the packets to their corresponding network ports. An image analysis method involves producing by a camera an indication whether a region of an image differs by a threshold extent from a corresponding region of a reference image; transmitting the indication and image data to a controller via a communications network; and storing at the controller the image data and the indication in association therewith. The controller may perform operations according to positive indications. A transmission method involves receiving user input in respect of a video stream and transmitting, in accordance with the user input, selected data packets of selected image frames thereof.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to multi-apparatus electronic systems and, inparticular, to a method, system and apparatus for image capture,analysis and transmission.

2. Description of Related Art

Link aggregation (also known as trunking or inverse multiplexing) refersto the use of multiple network paths in a communications link toincrease data transmission speed, reliability through the use ofredundant transmission, or increase both speed and reliability of thelink beyond that of a comparable link having a single network path.

Communications equipment specifically capable of providing linkaggregation has been manufactured by various equipment manufacturers,however, such components are limited to use with interconnectingequipment from the same manufacturer or even the same product line. U.S.Pat. No. 5,608,733 to Vallee et al. discloses ATM (Asynchronous TransferMode) inverse multiplexing in which digital data in ATM cells are sentto a destination node over more than one transmission link in roundrobin fashion, however, such ATM inverse multiplexing requires the useof a protocol calling for a physical layer OAM (Operation Administrationand Maintenance) cell that is defined to be exclusively processed by theATM inverse multiplexers.

Some communications equipment constitute multi-port network interfaceshaving link aggregation capabilities. Such network interfaces comprise anetwork interface card and associated device driver software, butrequire the installation and configuration of device driver layersoftware specific to and compatible with specific multi-port networkinterface cards having link aggregation capabilities. The U.S. Pat. No.6,873,630 issued to Muller et al. discloses a multi-gigabit ethernetarchitecture in which a communication for transmission across a networkby a first network entity is divided for transmission across multiplechannels at a point below the Medium Access Control (MAC) layer ofoperation. However, such architecture requires the use of hardwarecomponents having compatible link aggregation capabilities below the MAClayer of operation.

Some multi-port network interfaces provide link aggregation by emulatinga single port network interface. Such emulating network interfacesredirect a network packet received from a source entity to one of themultiple paths by overwriting specific header information of the networkpacket; and direct a network packet received from one of the multiplenetwork paths to the destination entity by overwriting headerinformation of the network packet to make it appear to the destinationentity as if transmission had occurred via a single port networkinterface. However, such emulating network interfaces introducetransmission inefficiencies by their need to overwrite headerinformation of the network packets being transmitted.

Some operating systems include kernel functions that support the use ofmulti-port network interface cards for link aggregation, however, suchoperating systems are limited to the use of multi-port network interfacecards specifically compatible with the particular kernel of theoperating system.

Thus, there is a need for scalable link aggregation techniques notlimited by the compatibility requirements of prior systems and by theneed for installation and configuration of specific communicationsequipment or network interfaces themselves having link aggregationcapabilities.

Image analysis refers to producing meaningful data and information inresponse to images. Digital Video Recorders (DVR) digitally record videosignals received in analog format via cable connection from one or morecameras.

U.S. Pat. No. 7,340,151 issued to Taylor et al. discloses a method bywhich a DVR, at the time of storing a received video signal, alsogenerates and stores metadata identifying spatial regions of motion. Themethod involves creating a spatial grid of zones and assigning a bitvalue to one motion bit for each zone, thereby indicating the presenceor absence of motion in each zone. The motion bits can be logically“OR'd” to facilitate subsequent processing. However, the method ofTaylor et al. is limited to generating metadata in a DVR that isdirectly connected by cable to a camera transmitting an analog videosignal across the cable connection. Thus, the DVR is not suitable foruse in systems where images captured by a camera are transmitted acrossa communications network.

Transmitting a video from a server to a client computer by streamingdata packets of the video permits the client computer to display imagesof the video in a viewing window on a monitor connected to the clientcomputer. The viewing window has a viewing window area measured in widthof pixels by height of pixels. For example, a viewing window that is 800pixels wide by 600 pixels high has a viewing window area of 0.48Megapixels (MP). The viewing window area is a measure of the image sizebeing displayed. Video images can be captured, transmitted and displayedat a frame rate, measured in frames/second (fps).

U.S. Pat. No. 6,172,672 issued to Ramasubramanian et al. discloses amethod and system for delivering video from a server to a client over acommunication medium with a limited bandwidth. Different versions of avideo are stored as pre-compressed video files using differentcompression ratios. The server is configured to switch between videofile sources to provide increased quality slow motion video at a second,slower frame rate than an initial predetermined frame rate, or toprovide still “snapshot” of a particular frame selected from aleast-compressed video file. If pre-compressed video data is notpre-compressed to the degree required to be able to transmit the videoto a client for normal-speed playback in real time, some additionalon-the-fly compression must be performed to send the video to the clientfor normal-speed, real-time playback. However, transmission efficiencyis not optimized by the method and system of Ramasubramanian et al.

Objects of the invention include addressing the above shortcomings.

SUMMARY

The above shortcomings may be addressed by providing, in accordance withone aspect of the invention, a method of transmitting data by scalablelink aggregation from a source device having a central processing unitto a controller device, the source device and the controller devicebeing connected to a communications network and associated with asubnetwork of the communications network. The method involves: (a)identifying by the controller device to the source device one or morenetwork ports of the controller device; (b) producing by the sourcedevice a plurality of network packets comprising the data, each of thenetwork packets being associated with a corresponding network port ofthe one or more network ports, the corresponding network port beingselected by the central processing unit for substantially uniformselection of the one or more network ports; and (c) transmitting eachnetwork packet from the source device to the corresponding network port,respectively.

Producing by the source device a plurality of network packets comprisingthe data, each of the network packets being associated with acorresponding network port of the one or more network ports, thecorresponding network port being selected by the central processing unitfor substantially uniform selection of the one or more network ports,may involve selecting the corresponding network port by round robinselection. Transmitting each network packet from the source device tothe corresponding network port, respectively, may involve transmittingeach network packet from the source device to a switching deviceoperable to direct each network packet to the controller device at thecorresponding network port, respectively. Identifying by the controllerdevice to the source device one or more network ports of the controllerdevice may involve identifying the one or more network ports to acamera. Producing by the source device a plurality of network packetscomprising the data, each of the network packets being associated with acorresponding network port of the one or more network ports, thecorresponding network port being selected by the central processing unitfor substantially uniform selection of the one or more network ports,may involve producing by the camera the plurality of network packets inresponse to image data produced by the camera, the image datarepresenting a plurality of images captured by the camera. Producing bythe camera the plurality of network packets in response to image dataproduced by the camera, the image data representing a plurality ofimages captured by the camera, may involve compressing digitalrepresentations of the plurality of images. Producing by the sourcedevice a plurality of network packets comprising the data, each of thenetwork packets being associated with a corresponding network port ofthe one or more network ports, the corresponding network port beingselected by the central processing unit for substantially uniformselection of the one or more network ports, may involve selecting by thecentral processing unit of the camera the corresponding network port byround robin selection. The method may further involve producing by thecamera an indication whether a region of an image of the plurality ofimages differs from a corresponding region of a reference image by athreshold extent; and wherein producing by the source device a pluralityof network packets comprising the data comprises producing the pluralityof network packets in response to the indication and a portion of theimage data representing the image.

In accordance with another aspect of the invention, there is provided acomputer program product comprising computer-executable instructionsembodied in a computer-readable medium for performing a method oftransmitting data by scalable link aggregation from a source devicehaving a central processing unit to a controller device, the sourcedevice and the controller device being connected to a communicationsnetwork and associated with a subnetwork of the communications network.The method involves: (a) identifying by the controller device to thesource device one or more network ports of the controller device; (b)producing by the source device a plurality of network packets comprisingthe data, each of the network packets being associated with acorresponding network port of the one or more network ports, thecorresponding network port being selected by the central processing unitfor substantially uniform selection of the one or more network ports;and (c) transmitting each network packet from the source device to thecorresponding network port, respectively.

In accordance with another aspect of the invention, there is provided amethod of analyzing a plurality of images captured by a camera, themethod comprising: (a) producing by the camera an indication whether aregion of an image of the plurality of images differs from acorresponding region of a reference image by a threshold extent; (b)transmitting by the camera via a communications network to a controllerdevice the indication and image data representing the image; and (c)storing by the controller device the image data and the indication inassociation therewith.

The method may further involve producing by the camera scaled image dataassociated with the image. Producing by the camera an indication whethera region of an image of the plurality of images differs from acorresponding region of a reference image by a threshold extent mayinvolve comparing a pixel of the scaled image data with a correspondingpixel of scaled reference image data representing the reference image.Producing by the camera scaled image data associated with the image mayinvolve scaling down digital representations of each of the plurality ofimages. Producing by the camera an indication whether a region of animage of the plurality of images differs from a corresponding region ofa reference image by a threshold extent may involve setting a digitalbit to indicate whether the pixel differs from the corresponding pixelby the threshold extent, thereby indicating whether motion is occurringwithin the region. The method may involve receiving by the camera fromthe controller device the value of a user configurable thresholddefining the threshold extent. The method may involve performing by thecontroller device, if the indication is positive, one or more operationsselected from the group consisting of: (i) storing at least a portion ofthe image data, the portion being associated with the region; (ii)displaying the portion; (iii) performing one or more image analysisoperations on the portion; (iv) producing a user message; and (v)producing a signal for triggering an event. Performing by the controllerdevice, if the indication is positive, one or more operations, selectedfrom the group consisting of: storing at least a portion of the imagedata, the portion being associated with the region; displaying theportion; performing one or more image analysis operations on theportion; producing a user message; and producing a signal for triggeringan event, may involve performing a selected operation if the indicationindicates motion occurring within the region. Producing a signal fortriggering an event may involve producing an actuation signal foractuating an external device. The method may involve producing the imagedata by compressing a digital representation of the image. Producing bythe camera an indication whether a region of an image of the pluralityof images differs from a corresponding region of a reference image by athreshold extent may involve selecting as the reference image aconsecutive image captured by the camera immediately prior to capturingthe image. Transmitting by the camera via a communications network to acontroller device the indication and image data representing the imagemay involve transmitting the indication and the image data by scalablelink aggregation when the camera and the controller device are eachassociated with a subnetwork of the communications network.

In accordance with another aspect of the invention, there is provided asystem for analyzing a plurality of images. The system includes: (a)imaging means for capturing the plurality of images, the imaging meansbeing operable to produce image data representing an image of theplurality of images and to produce an indication whether a region of theimage differs from a corresponding region of a reference image; (b)switching means for receiving from the imaging means the indication andthe image data, the switching means being operable to direct theindication and the image data to controller means via a communicationsnetwork; and (c) the controller means operable to store the image dataand the indication in association therewith.

Controller means may be operable to perform, if the indication ispositive, one or more operations selected from the group consisting of:(i) storing at least a portion of the image data, the portion beingassociated with the region; (ii) displaying the portion; (iii)performing one or more image analysis operations on the portion; (iv)producing a user message; and (v) producing a signal for triggering anevent. The imaging means and the controller means may be associated witha subnetwork of the communications network. The controller means mayinclude one or more network ports. The imaging means may includeprocessing means operable to produce the indication. The processingmeans may be operable to produce a plurality of network packetscomprising the image data and the indication. The processing means maybe operable to associate each the network packet with a correspondingnetwork port of the one or more network ports. The imaging means may beoperable to transmit the plurality of network packets to the switchingmeans. The switching means may be operable to direct the each networkpacket to the controller means at the corresponding network port,respectively.

In accordance with another aspect of the invention, there is provided acamera. The camera includes: (a) an image sensor for capturing aplurality of images; (b) a processor for producing image data inresponse to an image of the plurality of images, the processor beingoperable to produce an indication whether a region of the image differsfrom a corresponding region of a reference image by a threshold extent;and (c) a network interface for transmitting to a controller device viaa communications network the image data and the indication. Theprocessor may be operable to produce scaled image data by scaling downthe image data. The processor may be operable to compare a pixel of thescaled image data with a corresponding pixel of scaled reference imagedata representing the reference image. The processor may be operable toset a digital bit to indicate whether the pixel differs from thecorresponding pixel by the threshold extent such that the digital bitindicates whether motion is occurring within the region. The processormay be operable to determine the value of a user configurable thresholddefining the threshold extent. The processor may be operable to receivethe value from the controller device. The processor may be operable toproduce compressed data by compressing a digital representation of theimage. The camera may be operable to transmit the compressed data to thecontroller device by scalable link aggregation when the camera and thecontroller device are each associated with a subnetwork of thecommunications network.

In accordance with another aspect of the invention, there is provided amethod of streaming a video, the video including a plurality of imageframes having associated therewith a source frame rate, each of theimage frames having associated therewith a source pixel resolution, eachof the image frames including a plurality of data packets. The methodinvolves: receiving as user input a viewing area of a viewing window, animage region, and a display quality bias; and transmitting a selectionof the image frames and, for each of the selected image frames,transmitting a data packet selection of the data packets associated onlywith the image region and a pixel resolution determined in response tothe viewing area, the display quality bias and the source pixelresolution.

The method may involve receiving as user input a chromatic specificationselected from the group consisting of a monochromatic selection and acolour selection. The method may involve transmitting only monochromeinformation of the video stream if the chromatic specification isselected as the monochrome selection. The method may involve receivingas user input the display quality bias selected from the groupconsisting of: a maximum quality, a high quality, a medium quality and alow quality. The method may involve determining a permitted pixelresolution equal to the source pixel resolution divided by the result offour raised to an integer power. The method may involve determining theinteger power such that the permitted pixel resolution is equal to aparticular the permitted pixel resolution closest to and greater than orequal to the viewing area if the display quality bias is selected as themaximum quality, equal to one fourth of the particular permitted pixelresolution if the display quality bias is selected as the high quality,equal to one sixteenth of the particular permitted pixel resolution ifthe display quality bias is selected as the medium quality and equal toone sixty-fourth of the particular permitted pixel resolution if thedisplay quality bias is selected as the low quality. The method mayfurther involve assigning the pixel resolution to the lesser of thepermitted pixel resolution and the source pixel resolution. The methodmay involve selecting the selection of the image frames such that astream bandwidth limit is not exceeded. Selecting the selection of theimage frames such that a stream bandwidth limit is not exceeded mayinvolve receiving as user input a bandwidth limit associated with atransmission link, and setting the stream bandwidth limit equal to thebandwidth limit divided by a number of the videos being transmitted viathe transmission link. Selecting the selection of the image frames suchthat a stream bandwidth limit is not exceeded may involve determining aframe size of the data packet selection, determining a frame rate limitequal to the stream bandwidth limit divided by the frame size, selectingthe image frames if the frame rate limit is greater than or equal to thesource frame rate, and, if the frame rate limit is less than the sourceframe rate, selecting a subset of the image frames such that atransmission rate of the subset is less than or equal to the frame ratelimit. The method may involve selecting the subset so as to produce asubstantially uniform temporal distribution of the selected imageframes. Determining a frame size of the data packet selection mayinvolve determining an average frame size associated with a plurality ofthe selected image frames.

In accordance with another aspect of the invention, there is provided asystem for streaming a video, the video including a plurality of imageframes having associated therewith a source frame rate, each of theimage frames having associated therewith a source pixel resolution, eachof the image frames including a plurality of data packets. The systemincludes: (a) a client operable to receive as user input a viewing areaof a viewing window, an image region, and a display quality bias; and(b) a controller device operable to transmit a selection of the imageframes to the client and, for each of the selected image frames,transmitting a data packet selection of the data packets associated onlywith the image region and a pixel resolution determined in response tothe viewing area, the display quality bias and the source pixelresolution.

The client may be operable to receive as user input a chromaticspecification selected from the group consisting of a monochromaticselection and a colour selection. The controller device may be operableto transmit monochrome information only of the video stream when thechromatic specification is selected as the monochrome selection. Theclient may be operable to receive as user input the display quality biasselected from the group consisting of: a maximum quality, a highquality, a medium quality and a low quality. The client may be operableto determine a permitted pixel resolution equal to the source pixelresolution divided by the result of four raised to an integer power. Theclient may be operable to determine the integer power such that thepermitted pixel resolution is equal to a particular the permitted pixelresolution closest to and greater than or equal to the viewing area ifthe display quality bias is selected as the maximum quality, equal toone fourth of the particular permitted pixel resolution if the displayquality bias is selected as the high quality, equal to one sixteenth ofthe particular permitted pixel resolution if the display quality bias isselected as the medium quality and equal to one sixty-fourth of theparticular permitted pixel resolution if the display quality bias isselected as the low quality. The client may be operable to assign thepixel resolution to the lesser of the permitted pixel resolution and thesource pixel resolution. The client may be operable to communicate tothe controller device the pixel resolution. The controller device may beoperable to select the selection of the image frames such that a streambandwidth limit is not exceeded. The client may be operable to receiveas user input a bandwidth limit associated with a transmission link. Theclient may be operable to set the stream bandwidth limit equal to thebandwidth limit divided by a number of the videos being received by theclient via the transmission link. The client may be operable tocommunicate to the controller device the stream bandwidth limit. Thecontroller device may be operable to determine a frame size of the datapacket selection. The controller device may be operable to determine aframe rate limit equal to the stream bandwidth limit divided by theframe size. The controller device may be operable to select the imageframes if the frame rate limit is greater than or equal to the sourceframe rate. The controller device may be operable to, if the frame ratelimit is less than the source frame rate, select a subset of the imageframes such that a transmission rate of the subset is less than or equalto the frame rate limit. The controller device may be operable to selectthe subset so as to produce a substantially uniform temporaldistribution of the selected image frames. The controller device may beoperable to determine an average frame size associated with a pluralityof the selected image frames.

In accordance with another aspect of the invention, there is provided asystem for streaming a video, the video including a plurality of imageframes having associated therewith a source frame rate, each of theimage frames having associated therewith a source pixel resolution, eachof the image frames including a plurality of data packets. The systemincludes: (a) receiving means for receiving as user input a viewing areaof a viewing window, an image region, and a display quality bias; and(b) transmitting means for transmitting a selection of the image framesand, for each of the selected image frames, transmitting a data packetselection of the data packets associated only with the image region anda pixel resolution determined in response to the viewing area, thedisplay quality bias and the source pixel resolution.

The receiving means may be operable to receive as user input a chromaticspecification selected from the group consisting of a monochromaticselection and a colour selection. The transmitting means may be operableto transmit monochrome information only of the video stream when thechromatic specification is selected as the monochrome selection. Thesystem may include data packet selecting means for selecting the datapacket selection. The system may include frame selecting means forselecting the selected image frames.

Other aspects and features of the present invention will become apparentto those of ordinary skill in the art upon review of the followingdescription of embodiments of the invention in conjunction with theaccompanying figures and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate by way of example only embodiments of theinvention:

FIG. 1 is a block diagram of a system operable according to embodimentsof the invention to transmit data by scalable link aggregation and toperform image analysis;

FIG. 2 is a flow diagram of a method of the system shown in FIG. 1 oftransmitting data between a source device and a controller device byscalable link aggregation in accordance with a first embodiment of theinvention;

FIG. 3 is a flow diagram of an exemplary method of performing the stepshown in FIG. 2 of transmitting identifications of one or morecontroller network ports, showing communications between a camera and aserver;

FIG. 4 is a flow diagram of an exemplary method of performing the stepshown in FIG. 2 of producing a plurality of network packets associatedwith corresponding controller network ports selected by a source deviceCentral Processing Unit (CPU) for substantially uniform selection;

FIG. 5 is a flow diagram of an exemplary method of performing the stepshown in FIG. 2 of transmitting each network packet for reception by thecontroller device at its corresponding network port, showingcommunications between the camera, a switch and the server;

FIG. 6 is a flow diagram of a method of the system shown in FIG. 1 ofanalyzing a plurality of images according to a second embodiment of theinvention;

FIG. 7 is a flow diagram of an exemplary method of performing the stepsshown in FIG. 6 of selecting regions and producing indications whethereach region differs from a corresponding region by a threshold extent,showing a selected pixel of an image being compared with a correspondingpixel of a reference image;

FIG. 8 is a flow diagram of an exemplary method of performing the stepshown in FIG. 6 of transmitting indications and image data, showing eachnetwork packet being associated with a corresponding server network portselected by the camera CPU for substantially uniform selection;

FIG. 9 is a flow diagram of an exemplary method of performing the stepshown in FIG. 6 of performing operations according to user settings,showing performing image analysis on a portion of the image dataassociated with a positive indication;

FIG. 10 is a block diagram of a system operable according to a thirdembodiment of the invention to stream a video;

FIG. 11 is a flow diagram of a method of the system shown in FIG. 10 ofstreaming a video in accordance with the third embodiment;

FIG. 12 is a flow diagram of an exemplary method of performing the stepshown in FIG. 11 of receiving user input in respect of a video stream;and

FIG. 13 is a flow diagram of an exemplary method of performing the stepshown in FIG. 11 of transmitting in accordance with the user inputselected data packets of selected image frames of the video stream.

DETAILED DESCRIPTION

A system for analyzing a plurality of images includes: imaging means forcapturing said plurality of images, said imaging means being operable toproduce image data representing an image of said plurality of images andto produce an indication whether a region of said image differs from acorresponding region of a reference image; switching means for receivingfrom said imaging means said indication and said image data, saidswitching means being operable to direct said indication and said imagedata to controller means via a communications network; and saidcontroller means operable to store said image data and said indicationin association therewith. The controller means may be operable toperform, if said indication is positive, one or more operations selectedfrom the group consisting of: storing at least a portion of said imagedata, said portion being associated with said region; displaying saidportion; performing one or more image analysis operations on saidportion; producing a user message; and producing a signal for triggeringan event. The imaging means may comprise processing means operable toproduce said indication. The imaging means may comprise processing meansoperable to produce a plurality of network packets comprising said imagedata and to associate each said network packet with a correspondingnetwork port of said controller means.

Referring to FIG. 1, the system is shown generally at 10. The system 10according to a first and preferred embodiment of the invention isoperable to transmit data by scalable link aggregation.

The system 10 includes one or more source devices 12, each of which maybe any device operable to act as a source of a digital communication,including any imaging device such as the camera 14; any communicationsdevice such as a portable communications device, facsimile machine,telephone, including a land-line-connected or a wireless telephone suchas a cellular or satellite telephone, radio, including a two-way radio,personal digital assistant, modem, or other equipment unit suitable forelectronic communications; any computing device such as a generalpurpose computer, microcomputer, minicomputer, mainframe computer,distributed network for computing; any functionally equivalent discretehardware components; and any combination thereof, for example.

FIG. 1 shows each source device 12 as having an image sensor 16 forcapturing images, such as in the exemplary case where each source device12 is a camera 14. The camera 14 is preferably a digital video camera,and the image sensor 16, the CPU 20 or both the image sensor 16 and theCPU 20 may be operable to produce digital representations of imagesbeing captured by the camera 14.

FIG. 1 also shows each source device 12 as having a Network InterfaceCard (NIC) 18 operable to provide a network interface for facilitatingexternal communications of each source device 12. Although the exemplaryNIC 18 is shown in FIG. 1 is illustrated as a single port NIC, it iswithin the scope contemplated by the present invention for any NIC 18 ofthe one or more source devices 12 to include multiple ports of anynumber and to have multiple-port capabilities. It is advantageously notnecessary for the proper operation of the present invention to requirethe NIC 18 itself to have link aggregation capabilities.

Embedded within each source device 12 and shown in FIG. 1 between theimage sensor 16 and the NIC 18 is a Central Processing Unit (CPU) 20operable to control operations of the source device 12 separate from anyoperations internal to the NIC 18 itself.

In communication with the CPU 20 is a memory circuit 22 operable tostore data and computer program instructions.

In various embodiments the CPU 20 may be implemented by any processingcircuit having one or more circuit units, including a digital signalprocessor (DSP), embedded processor, etc., and any combination thereofoperating independently or in parallel, including possibly operatingredundantly. Such processing circuit may be implemented by one or moreintegrated circuits (IC), including being implemented by a monolithicintegrated circuit (MIC), an Application Specific Integrated Circuit(ASIC), a Field Programmable Gate Array (FPGA), etc. or any combinationthereof. Additionally or alternatively, such processing circuit may beimplemented as a programmable logic controller (PLC), for example. TheCPU 20 may include circuitry for storing memory, such as digital data,and may comprise the memory circuit 22 or be in wired communication withthe memory circuit 22, for example.

Typically, the memory circuit 22 is all or part of a digital electronicintegrated circuit or formed from a plurality of digital electronicintegrated circuits. The memory circuit 22 may be implemented asRead-Only Memory (ROM), Programmable Read-Only Memory (PROM), ErasableProgrammable Read-Only Memory (EPROM), Electrically ErasableProgrammable Read-Only Memory (EEPROM), flash memory, one or more flashdrives, universal serial bus (USB) connected memory units, magneticstorage, optical storage, magneto-optical storage, etc. or anycombination thereof, for example. The memory circuit 22 may be operableto store memory as volatile memory, non-volatile memory, dynamic memory,etc. or any combination thereof.

Each source device 12 is preferably operable to run any one or moreoperating systems (O/S) 24, including real-time operating systems suchas WinCE, Symbian, OSE and Embedded LINUX for example, non-real-timeoperating systems such as Linux, Windows and Unix for example, and anycombination thereof.

Each source device 12 is preferably operable to execute operations inaccordance with network interface driver software instructions such asthe NIC driver 26 shown conceptually in FIG. 1. The NIC driver 26 istypically installed in the memory circuit 22 for execution by the CPU 20in accordance with the manufacturer's instructions of the particular NIC18 installed in the source device 12. The present invention isadvantageously operable without restriction on the types of the NIC 18and its associated NIC driver 26. The system 10 is advantageouslyoperable to provide link aggregation without requiring the NIC 18 itselfto have link aggregation capabilities.

As shown in FIG. 1, each source device 12 can be connected via a sourceconnection 28 to a switching device such as the network switch 30. Thenetwork switch 30 is typically operable to receive, at any one of itsone or more switching device input ports 32, communication data such asa network packet. As is well known in the art, a network packet containsheader information specifying a destination address for the intendeddestination of the network packet. In ordinary operation, the networkswitch 30 receives a network packet at one of its switching device inputports 32, and then transmits the received network packet from theparticular one of its one or more switching device output ports 34 thatis connected to the intended destination via the controller connection36.

The controller connection 36 is shown in FIG. 1 as being directlyconnected to a controller device 38, which in some embodiments may beimplemented as a server 40 as shown in FIG. 1. The controller connection36 is shown in FIG. 1 as being directly connected to the controllerdevice 38 at its multi-port Network Interface Card (NIC) 42. AlthoughFIG. 1 shows the exemplary implementation of the controller device 38 asone server 40, the controller device 38 may in various embodiments ofthe present invention be any device identical, similar, analogous to ordifferent from the source device 12 and the system 10 may include one ormore controller devices 38, for example. It is advantageously notnecessary for the proper operation of the present invention to requirethe multi-port NIC 42 itself to have link aggregation capabilities. Thesystem 10 is advantageously operable to provide link aggregation with orwithout the use of the switch 30 in any embodiments (not shown) in whichone source device 12 having a multiple port network interface isconnected via parallel network paths from its multiple ports tocorresponding ports of a multiple port network interface of onecontroller device 38. While FIG. 1 shows a single switch 30 connectedbetween the one or more source devices 12 and the controller device 38,in general any number of switching devices, networking components and/orconnections may be used to provide a connection from one or more portsof the source NIC 18 to one or more ports of the NIC 42, providedpreferably that each source device 12 and each controller device 38 areconnected to the same subnetwork of a common communications network. Thesource connections 28 and the controller connections 36, and any portionthereof, may be any wired or wireless connection, including a copperwire link, a coaxial cable link, a fiber-optic transmission link, aradio link, a cellular telephone link, a satellite link, a line-of-sightfree optical link, and any combination thereof, for example. The sourceconnections 28 and the controller connections 36, and any portionthereof, form part or all of a communications network, such as theInternet for example. The transmission of network packets across thecommunications network may involve encrypted or otherwise securecommunications.

The controller device 38 preferably includes a processing circuit, anexample of which is shown in FIG. 1 as the server processor 44, and amemory circuit, an example of which is shown in FIG. 1 as the servermemory 46.

The server processor 44 is typically a processing circuit that includesone or more circuit units, such as a central processing unit (CPU),digital signal processor (DSP), embedded processor, etc., and anycombination thereof operating independently or in parallel, includingpossibly operating redundantly. The server processor 44 may beimplemented in a manner identical, similar, analogous to or differentfrom the CPU 20, for example. The server processor 44 may includecircuitry for storing memory, such as digital data, and may comprise theserver memory 46 or be in wired communication with the server memory 46,for example.

The server memory 46 is typically all or part of a digital electronicintegrated circuit or formed from a plurality of digital electronicintegrated circuits. The server memory 46 may be implemented and may beoperable to store memory in a manner identical, similar, analogous to ordifferent from the memory circuit 22. The server memory 46 preferablyincludes controller device 38 components, and in some embodiments mayinclude a database (not shown) external to the controller device 38.

The controller device 38 is typically operable to run any one or moreoperating systems (O/S) identical, similar, analogous to or differentfrom that or those of the source devices 12, including the exemplaryserver O/S 48 shown in FIG. 1. The controller device 38 may be operableto implement multi-tasking methods involving multiple threads ofexecutable code, for example.

The controller device 38 is preferably operable to execute operations inaccordance with network interface driver software instructions such asthe server NIC driver 50 shown conceptually in FIG. 1. The server NICdriver 50 is typically installed in the server memory 46 for executionby the server processor 44 in accordance with the manufacturer'sinstructions of the particular NIC 42 installed in the controller device38. The present invention is advantageously operable without restrictionon the types of the NIC 42 and its associated NIC driver 50. The system10 is advantageously operable to provide link aggregation withoutrequiring the NIC 42 itself to have link aggregation capabilities.

Method of Scalable Link Aggregation

Referring to FIG. 2, the memory circuit 22 in accordance with a firstembodiment of the invention contains blocks of code comprising computerexecutable instructions for directing the CPU 20. Also, the servermemory 46 in accordance with the first embodiment contains blocks ofcode comprising computer executable instructions for directing theserver processor 44. Additionally or alternatively, such blocks of codemay form part of one or more computer program products comprisingcomputer executable instructions embodied in one or more signal bearingmedia, which may be one or more recordable computer-readable media orone or more signal transmission type media, for example.

When electrical power is being supplied to the CPU 20, the memorycircuit 22, the server processor 44 and the server memory 46, the CPU 20and the server processor 44 are directed in the first embodiment toperform respective steps of a method of the system 10 shown generally at52.

Method 52 begins execution at block 54, which directs the serverprocessor 44 to cause the controller device 38 to transmit to a sourcedevice 12 identifications of one or more controller network ports of themulti-port NIC 42.

Such transmission typically requires the establishment of communicationsbetween the controller device 38 and the source device 12 in accordancewith any communications protocol or standard, as may be well known inthe art. In various embodiments of the invention, the transmission ofidentifications of the one or more controller network ports of themulti-port NIC 42 may involve a single or multiple, including possiblyredundant, communications between the controller device 38 and one ormore of the source devices 12. In accordance with user settings of thecontroller device 38, all or only some of the network ports of themulti-port NIC 42 may be identified to the source devices 12 as acontroller network port for use in communications between the sourcedevices 12 and the controller device 38, although preferably a defaultcondition of the controller device 38 is to identify at least alloperational network ports of the controller device 38. Preferably, thetransmitted identifications are made available to all of the sourcedevices 12 connected to the same subnetwork of the communicationsnetwork to which the controller device 38 is connected.

In general, the system 10 is operable to cause the server 40 to identifyto the source device 12 any number of controller network ports that areoperational within the controller device 38. Thus, the number ofcontroller network ports available to the source device 12 in at leastsome embodiments is advantageously scalable in accordance with a usersetting or otherwise under the control of the user, including beingscalable by increasing the number of controller network ports presentand operational within the controller device 38. Additionally oralternatively, the number of controller network ports available to thesource device 12 may be all controller network ports that, upon startupof the controller device 38, are operational and associated with thesame subnetwork of the communications network to which the source device12 is connected. The number of controller network ports available to thesource device 12 may be varied by physically changing the number ofcontroller network ports during downtime of the controller device 38. Insome embodiments, the controller device 38 is operable to transmitupdated identifications to replace any existing identificationspreviously transmitted to the source device 12.

Thus, the number of controller network ports available to the sourcedevice 12 in the first embodiment is advantageously scalable inaccordance with the number of controller network ports made physicallyoperational and identified to a given source device 12.

In the exemplary circumstances in which at least one source device 12has received a request or command transmitted from the controller device38 to begin streaming data to the controller device 38, block 56 thendirects the CPU 20 of that at least one source device 12 to cause thatsource device 12 to produce a plurality of network packets associatedwith corresponding controller network ports selected by that CPU 20 forsubstantially uniform selection.

The network packets may contain any data for transmitting to thecontroller device 38. For example, the network packets may contain dataof a file transfer such as in circumstances of peer-to-peer networking,sensor data in circumstances of networked sensing equipment, image datain circumstances of networked imaging equipment such as the camera 14,etc. Additionally or alternatively, one or more network packets mayinclude a representation of time at which an event may have occur, suchas by including in a payload of the network packets time stampinformation.

In the first embodiment, the CPU 20 is operable to select from among thecontroller network ports identified to the source device 12 by block 54.Such controller network ports may be selected in any fashion and arepreferably selected for substantially uniform distribution of selectionsamong the identified controller network ports. For example, thecontroller network ports may be selected according to a ranking system,randomly, in response to data representing historical use of controllernetwork ports, by round robin selection in which the controller networkports are ordered from first to last (with the last being followed bythe first) and each new selection is the subsequent controller networkport in the round robin order, and any combination thereof.

It is within the scope of the present invention for the CPU 20 itself toproduce the network packets, for the CPU 20 to cause the NIC 18 toproduce the network packets, or any combination thereof including boththe CPU 20 itself and the NIC 18 producing the same or different networkpackets. Preferably, the source device 12 is operable to associate thecontroller network port selected for a given network packet with thatnetwork packet in any manner, including having the CPU 20 produce headerinformation of the network packet and/or having the CPU 20 communicateits selection to the NIC 18 for producing the header information of thenetwork packet.

Block 58 directs the CPU 20 to cause the at least one source device 12to transmit to the controller device 38 each network packet produced bythe source device 12, for reception by the controller device 38 at itscorresponding network port. In the first embodiment, the CPU 20 causesthe NIC 18 to transmit the network packet such that the communicationsnetwork, to which the source device 12 and the controller device 38 areconnected, directs the network packet to the controller device 38 at itsparticular controller network port associated with the network packet.The communications network may include the switch 30 (FIG. 1), forexample.

After block 58 has been executed, FIG. 2 shows that the method 52 ends.In various embodiments, the completion of blocks 54 to 58 may result ina return to an idle state of the system. Additionally or alternatively,any of blocks 54 to 58 may be re-executed, such as in exemplarycircumstances of data streaming where one or more network packetsproduced by executing block 56 are transmitted by executing block 58 andthen block 56 is re-executed to produce further network packets. Blocks56 and 58 may be iteratively executed until no further data is availablefor transmission or no further data transmission is requested, forexample.

Referring to FIG. 3, an exemplary method of performing steps of block 54(FIG. 2) is shown generally at 60. In the exemplary circumstances inwhich a given source device 12 is the camera 14 and the controllerdevice 38 is the server 40, method 60 begins execution at block 62,which directs the CPU 20 to cause the camera 14 to broadcast itspresence and identification within a subnetwork. Preferably, the CPU 20directs the NIC 18 to transmit a communication in accordance with anystandard or protocol that can identify the camera 14. The camera 14 inthe first embodiment is operable to broadcast transmit the communicationsuch that the communication is available for reception by all devicesconnected to the same subnetwork of the communications network to whichthe camera 14 is connected, preferably including the server 40.

Block 64 directs the server processor 44 to cause the server 40 toreceive the identification of the camera 14, such as by receiving at itsmulti-port NIC 42 the communication broadcast transmitted by the camera14.

Block 66 directs the server processor 44 to cause the server 40 totransmit to the camera 14 the identifications of its one or more servernetwork ports. Such server network ports are preferably those of themulti-port NIC 42 of the server 40 and may be any subset thereof. Insome embodiments, transmitting the identifications of the server networkports to the camera 14 involves broadcast transmitting one or morecommunications containing the identifications for reception by allsource devices 12 connected to the same subnetwork of the communicationsnetwork to which the server 40 is connected. In some embodiments,however, the communication may be transmitted specifically to theparticular camera 14 that had broadcast its identification by executingblock 62. In some embodiments, the server 40 is operable to transmitupdated identifications to replace any existing identificationspreviously transmitted to the camera 14.

After block 66 has been executed, the method 60 ends and operationcontrol is returned to block 56 (FIG. 2).

Referring to FIG. 4, an exemplary method for directing the CPU 20 toperform steps of block 56 (FIG. 2) in respect of a given camera 14 isshown generally at 68. Method 68 begins execution at block 70, whichdirects the CPU 20 to cause the camera 14 to capture a plurality ofsequential images of a video stream. The camera 14 is preferablyoperable to begin capturing images in response to a request received bythe camera 14 from the server 40, by manual operation of the camera 14,or by both or either of such communicated request and such manualoperation. In embodiments of the invention, images are captured by theimage sensor 16 of the camera 14.

Block 72 directs the CPU 20 to cause the camera 14 to produce image datarepresenting the plurality of sequential images. Preferably, the camera14 is operable to produce image data for each image of the plurality ofsequential images.

Preferably, the steps of blocks 70 and 72 are performed concurrently orsimultaneously, such as by the image sensor 16 capturing and digitizingthe plurality of sequential images to produce the image data. However,the scope of the present invention is not limited by any particulararrangement or operability of imaging and/or digitizing componentswithin the camera 14. For example, the image sensor 16 may produceanalog electronic signals that are subsequently digitized by othercomponents such as an analog-to-digital converter (not shown) of thecamera 14.

In the first embodiment, the camera 14 is operable to produce a digitalvideo stream, which may be considered to comprise digitalrepresentations of the plurality of sequential images.

Block 74 directs the CPU 20 to cause the camera 14 to produce one ormore indications indicating whether one or more regions of an image ofthe plurality of sequential images differs from corresponding regions ofa reference image by a threshold extent, respectively. For the purposesof the disclosure herein, a given image and the reference image may beconsidered to form a pair of images in which the given image is thefirst image and the reference image is the second image. In the firstembodiment, the first and second images are captured by the camera 14,and are captured at different times, including possibly one beingimmediately subsequent to the other, thereby rendering the first andsecond images consecutive. In the first embodiment, the second image isthe image in the plurality of sequential images immediately precedingthe first image. Additionally or alternatively, the system 10 in atleast some embodiments is operable to form the second image from amultiple number of captured images by combining such captured images toform the reference image such that it is representative of a staticbackground. In such embodiments, the system 10 is operable to create thereference image by extracting one or more static portions of images in asequence of images representing an unchanging scene. The digitalrepresentations of the static portions are combined to form digitalrepresentations of a static background image indicative of a lack ofmotion.

In the exemplary embodiment described herein, in respect of each pair ofimages, the CPU 20 is operable to cause the camera 14 to define a numberof regions of the first image, define the same number of regions of thesecond image corresponding to the regions of the first image, and tocompare the regions of the first image with the corresponding regions ofthe second image. Preferably, the CPU 20 is operable for each pair tocompare a given region of the first image and its corresponding regionof the second image in accordance with a comparison formula to determinewhether the region differs from its corresponding region by a thresholdextent. In the various embodiments, the value of the threshold definingthe threshold extent may be a fixed value determined duringmanufacturing of system 10 components, a fixed value determined duringinstallation of system 10 components, a user configurable value, or anycombination thereof including a user configurable value received fromthe controller device 38 for overriding, during operation of the camera14, a manufacturing or installation default value, for example.

The comparison formula may involve any relational operations betweendigital representations of any image features. For example, the value ofa data byte representing image data for a given region may be subtractedfrom the value of the data byte representing image data for thecorresponding region, and the value of the absolute difference comparedwith the value of the threshold. In the first embodiment, each regionand its corresponding region is compared to determine whether anydifferences therebetween are indicative of motion having occurredbetween the time the first image and the second image were captured. Ifthe region and its corresponding region differ by an extent greater thanthe value of the threshold, thereby indicating motion has occurred, thenthe indication is assigned a particular value such as a positive value.For example, the indication may be represented digitally by one digitalbit where a positive indication is represented by the bit value of ‘1’and a negative indication (indicating no detected motion or otherwiseinsufficient differences between the given region and its correspondingregion) is represented by the bit value of ‘0’, for example.

Block 76 directs the CPU 20 to cause the camera 14 to compress the imagedata to produce compressed image data representing the plurality ofsequential images captured by the camera 14. In general, the CPU 20 maybe directed to produce compressed data on the basis of the image dataalone, on the basis of the indications, or on the basis of both theimage data and the indications either compressed separately or together.Any suitable compression algorithm may be used, including lossy orlossless data compression, according to any suitable standard such asMPEG and others. In the first embodiment, the system 10 isadvantageously operable to produce the indications on the basis of theuncompressed image data having no loss of information, whiletransmitting compressed image data to the controller device 38, therebyreducing the transmission bandwidth required for such transmission.However, it is within the scope contemplated by the present inventionthat the indications are produced on the basis of compressed image dataor that uncompressed image data is transmitted, such as by linkaggregation, to the controller device 38. Nonetheless, in the preferredembodiment where an indication is produced on the basis of uncompressedimage data, block 76 may be executed before or after block 74, forexample.

Block 78 directs the CPU 20 to cause the camera 14 to produce networkpackets containing the compressed image data and the one or moreindications, and to associate each network packet with a correspondingserver 40 network port selected, by the CPU 20 from among the identifiedserver 40 network ports, by round robin selection. In the firstembodiment, each network packet includes at least one data frame orpayload containing at least a portion of the compressed image data, andincludes a digital representation of a destination address for oneserver 40 network port. Preferably, an identification of the destinationfor a given network packet is contained within header or other controlinformation of that network packet, such as by including in a header ortrailer frame the digital representation of the server 40 network port,thereby associating the network packet with its corresponding server 40network port destination. In some embodiments, the network packets maybe datagrams. In various embodiments of the invention, the camera 14 isoperable to produce network packets by the CPU 20 itself, by the NIC 18,by packet forming means (not shown) within or external to the camera 14,or any combination thereof for example.

In the first embodiment, the CPU 20 is directed by block 78 to selectthe server 40 network port for each network packet, therebyadvantageously facilitating the link aggregation features of the system10 while permitting the NIC 18 to be of any type, including any networkinterface not itself ordinarily capable of transmission by linkaggregation. In various embodiments, the CPU 20 is then directed toproduce network packets respectively containing therein identificationsof the selected server 40 network packets. Additionally oralternatively, the CPU 20 is in some embodiments operable to communicateto the NIC 18 or other packet forming means (not shown) the selectedserver 40 network packet for each network packet to be produced by suchpacket forming means. In the first embodiment, the CPU 20 is directed toselect the server 40 network packets by round robin selection.

As will be appreciated, the order of execution of blocks 70 to 78 may bevaried from their exemplary illustration in FIG. 4. For example, it iswithin the scope contemplated by the present invention for the CPU 20 tocause the camera 14 to capture one sequential image in accordance withblock 70, and process that one captured image in accordance with blocks72 to 78 before capturing a further image in accordance with block 70.Additionally or alternatively, processing of each captured image maycommence as soon as such image is captured in analog or digital formatand may proceed concurrently with further executions of block 70 or withblocks 70 and 72. In the first embodiment, the executions of blocks 70to 78 are streamed so as to produce a continuing video stream formattedas network packets respectively associated with corresponding server 40network ports.

Still referring to the exemplary illustration of FIG. 4, after block 78has been executed, the CPU 20 is directed to end the method 68 andreturn to the method 52 (FIG. 2) at block 58 thereof (FIG. 2).

Referring to FIG. 5, an exemplary method of the system 10 for performingsteps of block 58 (FIG. 2) is shown generally at 80, which beginsexecution at block 82. The CPU 20 is directed by block 82 to cause thecamera 14 to cause the camera 14 to transmit the network packets to theswitch 30. As illustrated in FIG. 1, the network packets produced byeach camera 14 are transmitted from their respective NICs 18 to acorresponding switching device input port 32 of the switch 30.

Block 84 directs the switch 30 of the system 10 to direct each networkpacket to the server 40 at its corresponding server 40 network port. Inthe first embodiment, each network packet contains a destination addressidentifying a server 40 network port corresponding to that networkpacket; and the switch 30 is operable to receive network packets at itsswitching device input ports 32, and direct each network packet to anappropriate switching device output port 34 such that each networkpacket is transmitted from the switch 30 to the server 40 at its server40 network port defined in accordance with the destination address foreach network packet.

Block 86 directs the server processor 44 to cause the server 40 toproduce a video stream in response to the network packets received bythe server 40. In the first embodiment, the server 40 is operable torecombine the network packets received from the various server 40network ports of the multi-port NIC 42 into a single, chronologicallyordered video stream. The system 10 is advantageously operable toproduce the video stream at the server 40 without requiring themulti-port NIC 42 to itself have link aggregation capabilities. Invarious embodiments, block 86 is executed automatically upon receipt ofthe network packets, only upon user request, in accordance with a usersetting, or any combination thereof for example. Additionally oralternatively, the server 40 may display the recombined video stream,request the re-transmission of specifiable network packets, or performother server 40 processing tasks in response to the received networkpackets, including storing contents of one or more of the receivednetwork packets in the server memory 46.

Still referring to FIG. 5, after block 86 has been executed the serverprocessor 44 is directed to end the method 80 and return to the method52 (FIG. 2).

Referring back to FIG. 2, after block 58 has been executed the method 52ends. In various embodiments, the system 10 is operable to end themethod 52 upon having produced and transmitted a fixed number of networkpackets or a fixed quantity of image data, having produced andtransmitted image data for a specifiable amount of time, having producedand transmitted image data for an indefinite amount of time untilreceiving a user command to cease, or any combination thereof forexample. It is within the scope contemplated by the present inventionfor the system 10 to produce by the source device 12 one network packetand transmit that one network packet for reception by the controllerdevice 38, then iteratively produce and transmit further networkpackets, for example. In the first embodiment, the system 10 is operableto stream the execution of blocks 56 and 58 such that a continuing videostream is produced and transmitted until a stop command is acted upon.

Thus, there is provided a method of transmitting data by scalable linkaggregation from a source device having a central processing unit to acontroller device, said source device and said controller device beingconnected to a communications network and associated with a subnetworkof said communications network, the method comprising: identifying bysaid controller device to said source device one or more network portsof said controller device; producing by said source device a pluralityof network packets comprising said data, each said network packet beingassociated with a corresponding network port of said one or more networkports, said corresponding network port being selected by said centralprocessing unit for substantially uniform selection of said one or morenetwork ports; and transmitting said each network packet from saidsource device to said corresponding network port, respectively.

Method of Image Analysis

Referring back to FIG. 1, the system 10 according to a second andpreferred embodiment of the invention is operable to analyze a pluralityof images.

In accordance with the second embodiment, the memory circuit 22 and theserver memory 46 contain blocks of code comprising computer executableinstructions for directing the CPU 20 and the server processor 44,respectively. Additionally or alternatively, such blocks of code mayform part of one or more computer program products comprising computerexecutable instructions embodied in one or more signal bearing media,which may be one or more recordable computer-readable media or one ormore signal transmission type media for example, in accordance with thesecond embodiment.

When electrical power is being supplied to the CPU 20, the memorycircuit 22, the server processor 44 and the server memory 46, the CPU 20and the server processor 44 are directed in the second embodiment toperform respective steps of a method of the system 10 shown generally inFIG. 6 at 88.

Referring to FIG. 6, the method 88 is illustrative of exemplary,non-limiting embodiments of the invention in which at least one sourcedevice 12 is a camera 14.

The method 88 begins when the server processor 44 is directed to beginexecuting instructions of block 90, which directs the server processor44 to cause the controller device 38 to receive one or more usersettings. Such user settings may include any configuration oroperational parameters, default values, specific values for overridingdefault values, or any combination thereof. In the second embodiment,the controller device 38 is operable to receive user settings as userinput during installation, configuration, operation, or any combinationthereof, of the controller device 38 for example.

Block 92 then directs the CPU 20 of the camera 14 to select an image. Ingeneral, such image may have been obtained by any means including havingbeen captured by an image sensor 16 of the camera 14. For the purposesof the disclosure herein, the selected image may be considered the firstimage of a pair of images in which the second image of the pair is areference image. Preferably, each subsequent iteration of block 92involves selecting as the first image a subsequently captured image of aplurality of images sequentially captured by the camera 14.

Selecting the first image may also include selecting the second image.Preferably, the first and second images are captured at different times,including possibly one being immediately subsequent to the other,thereby rendering the first and second images consecutive. In someembodiments, the reference image is a static background image indicativeof a lack of motion. In general, the second image may be selected at anytime prior to executing block 94 (described below).

Block 94 directs the CPU 20 to cause the camera 14 to select a region ofthe first image and a corresponding region of the reference image. Inthe second embodiment, each region is a section of an image, and a givenregion and its corresponding region are selected in respect ofcorresponding sections of their respective images. Executing block 94may also involve selecting reference image data representing thereference image. In the second embodiment, the camera 14 is operable toselect the reference image as the image of the plurality of images thatimmediately precedes the first image. In some embodiments, the referenceimage is selected as a static background image.

Block 96 directs the CPU 20 to cause the camera 14 to produce anindication whether the region (selected by block 94) differs from thecorresponding region by a threshold extent. In various embodiments, thecamera 14 is operable to determine whether the region differs from thecorresponding region in any suitable manner, including but not limitedto making such determination in accordance with a comparison formula. Inthe second embodiment, the camera 14 is operable to determine whetherany differences between the region and the corresponding are indicativeof motion having occurred within the section of the captured imagesassociated with region and corresponding region, and to produce apositive indication if motion is detected.

Blocks 94 and 96 may be implemented in any manner identical, similar,analogous or different from that of block 74 (FIG. 4), for example.

Block 98 directs the CPU 20 to determine whether there are more regionsof the first image to be compared with corresponding regions of thesecond image.

If the CPU 20 determines by block 98 that there are more regions, thenthe CPU 20 is directed to execute block 94 again. In the secondembodiment, blocks 94 to 98 are executed until indications have beenproduced for all defined regions and corresponding regions of the firstand second images.

Referring to FIG. 7, an exemplary method for directing the CPU 20 toperform steps of blocks 94 to 98 (FIG. 6) is shown generally at 100. Inthe exemplary circumstances in which the controller device 38 is theserver 40, method 100 begins execution at block 102, which directs theCPU 20 to cause the camera 14 to receive from the server 40 a thresholdvalue. While shown in FIG. 7 as the first block of the method 100, it isalso within the scope contemplated by the present invention for thecamera 14 to receive such threshold value at any time prior to its useduring execution of the method 100, such as during initialization of thecamera 14 for example. Additionally or alternatively, the camera 14 isoperable in some embodiments to determine, such as by receiving from theserver 40, an updated threshold value to replace any existing thresholdvalue previously obtained.

Block 104 directs the CPU 20 to cause the camera 14 to produce scaledimage data by scaling down a digital representation of the image. Forthe purposes of the disclosure herein, the image may be considered thefirst image of a pair of images in which the second image is a referenceimage. Scaling down the digital representation of the first image may beperformed by any suitable method, such as by averaging image datacorresponding to each defined section of the first image. In the secondembodiment, the camera 14 is operable to define sections of a givenimage, such as sections of 16 pixels by 16 pixels each; to determinedigital representations representing each section; to compute an averagefor each section; to represent each average as a digital representationof a single pixel associated with each respective section; and tocollate the averaged pixels to form scaled image data. In exemplaryembodiments where one pixel is determined for each section of 16 by 16pixels of the original image data, the scaled image data is scaled downfrom the original image data by a factor of 256, that number being theproduct of 16 and 16.

Block 106 directs the CPU 20 to cause the camera 14 to select a pixel ofthe first image and a corresponding pixel of the reference image.Preferably, the CPU 20 selects a pixel of the scaled image datarepresenting the first image and correspondingly scaled reference imagedata representing the reference image, although selecting a pixel orother region of original, unscaled image data is within the scope of thepresent invention.

Block 108 directs the CPU 20 to cause the camera 14 to compare the pixel(selected by executing block 106) and the corresponding pixel inaccordance with a comparison formula. While the comparison formula mayinvolve any relational operations between digital representations of anyimage features, the comparison formula in the second embodiment involvesa subtraction of the pixel and the corresponding pixel to obtain adifference value indicative of whether motion has occurred within thesection represented by the pixel and the corresponding pixel between thetime the first and second images were obtained.

Block 110 determines whether any differences determined by block 108between the pixel and the corresponding pixel are beyond the thresholdvalue obtained by block 102. Block 110 may be executed by comparing thedifference value of block 108 with the threshold value, therebyresulting in a determination as to whether the difference value isgreater than, equal to, or less than the threshold value.

If by executing block 110 the CPU 20 determines that the pixel and thecorresponding pixel differ by the threshold value, such as by thedifference value being equal to or greater than the threshold value,then the CPU 20 is directed to execute block 112.

Block 112 directs the CPU 20 to set a bit value to ‘1’, such as bysetting the bit value of an indication associated with the pixel andcorresponding pixel of the scaled image data, to indicate a positiveindication.

If by block 110 the CPU 20 determines that the pixel and thecorresponding pixel do not differ by the threshold value, such as by thedifference value being less than (or in variations of the embodiments,equal to or less than) the threshold value, then the CPU 20 is directedto execute block 114.

Block 114 directs the CPU 20 to set a bit value to ‘0’, such as bysetting the bit value of the indication associated with the pixel andcorresponding pixel of the scaled image data, to indicate a negativeindication.

In exemplary embodiments where the original images are scaled down by afactor of 256, each pixel is represented digitally by one 8-bit byte andeach indication constitutes one bit, the indications constitute 2048times less digital data than the original images.

Block 116 directs the CPU 20 to determine whether there are more pixelsof the first and second images available for analysis. If more pixelsare available, the CPU 20 is directed to re-execute blocks 106 to 114such that a new indication in respect of a new pixel and a newcorresponding pixel is determined.

If by block 116 the CPU 20 determines that there are no more pixelsassociated with the first and second images for performing imageanalysis, then the CPU 20 is directed to end the method 100 andoperation control is returned to block 118 of FIG. 6.

Referring back to FIG. 6, if the CPU 20 determines that there are nomore regions, including by having determined by block 116 (FIG. 7) thatthere are no more pixels, the CPU 20 is directed to execute block 118shown in FIG. 6.

Block 118 directs the CPU 20 to cause the camera 14 to transmit to thecontroller device 38 the indications and the image data representing thefirst image. Block 118 may be implemented in any manner identical,similar, analogous or different from that of block 58 of FIG. 2, forexample. In at least some embodiments, the system 10 is operable totransmit the indications and the image data by scalable linkaggregation, for example.

Referring to FIG. 8, an exemplary method for directing the CPU 20 toperform steps of block 118 (FIG. 6) is shown generally at 120. Themethod 120 begins execution at block 122, which directs the CPU 20 tocause the camera 14 to receive from the server 40 identifications of oneor more server 40 network ports. While shown in FIG. 8 as the firstblock of the method 120, it is also within the scope contemplated by thepresent invention for block 122 to be executed at any time prior toexecuting block 128 (described below), such as during initialization ofthe camera 14 for example. In some embodiments, the camera 14 isoperable to determine, such as by receiving from the server 40, updatedidentifications of server 40 network ports to replace any existingidentifications previously obtained.

Block 124 directs the CPU 20 to cause the camera 14 to producecompressed image data in response to the image data selected by block 92(FIG. 6). Block 124 may be implemented in any manner identical, similar,analogous or different from that of block 76 (FIG. 4), for example.

Block 126 directs the CPU 20 to cause the camera 14 to produce aplurality of network packets containing the compressed image data andthe indications associated with the compressed image data. Suchindications are preferably those produced by executing block 96 (FIG.6), including possibly in accordance with the method 100 (FIG. 7). Thecompressed image data is preferably that produced by executing block124. It is not necessary for the proper operation of the presentinvention for each network packet to include both image data and one ormore indications. Preferably, however, each indication, or digitalrepresentation thereof, is associated with the region and correspondingregion from which the indication was produced.

Block 128 directs the CPU 20 to cause the camera 14 to associate eachnetwork packet with a corresponding server 40 network port selected bythe CPU 20 for substantially uniform selection of the server 40 networkports identified by executing block 122. Block 128 may be implemented inany manner identical, similar, analogous or different from that of block78 (FIG. 4), for example.

Block 130 directs the CPU 20 to cause the camera 14 to transmit theplurality of network packets produced by block 126 to the server 40 atthe corresponding server 40 network ports selected by executing block128. In the second embodiment, the camera 14 is operable to transmit theplurality of network packets in any suitable manner and via anynetworking means having any intermediate connection(s) or device(s),including but not limited to transmitting the network packets via theswitch 30 shown in FIG. 1. Block 130 may be implemented in any manneridentical, similar, analogous or different from that of block 58 (FIG.2), for example.

Block 132 directs the server processor 44 to cause the server 40 tostore the indications contained within the network packets received bythe server 40 from the camera 14. Preferably, the indications are storedsuch that an association is maintained between the indications and thecompressed image data received by the server 40, whereby each indicationis associated with a portion of the compressed image data representingthe region from which each indication was produced, respectively. Theindications are preferably stored in the server memory 46, includingpossibly stored in a database external to the server 40.

Block 134 directs the server processor 40 to cause the server 40 toproduce a video stream in response to the received network packets.Block 134 may be implemented in any manner identical, similar, analogousor different from that of block 86 (FIG. 5), for example. In the secondembodiment, producing a video stream includes storing image datacontents of one or more of the received network packets in the servermemory 46, including possibly storing image data in a database externalto the server 40.

After block 134 is executed, the method 120 ends and operation controlis returned to the method 88 (FIG. 6) at block 136.

Referring back to FIG. 6, block 136 directs the server processor 44 tocause the controller device 38 to determine whether there are anypositive indications among the indications received from the camera 14.

If there is at least one positive indication, block 138 directs theserver processor 44 to cause the controller device 38 to perform one ormore operations in accordance with the user settings (previouslyobtained by executing block 90).

The system 10 is advantageously operable to perform operations on thebasis of the indications, including positive indications, produced inresponse to uncompressed image data without requiring uncompressed imagedata to be transmitted from a given source device 12 to the controllerdevice 38 and without requiring the given source device 12 itselfperform such operations.

Referring to FIG. 9, an exemplary method for directing the serverprocessor 44 to perform steps of block 138 (FIG. 6) is shown generallyat 140. The method 140 begins execution at block 142, which directs theserver processor 44 to cause the server 40 to store that portion of thevideo stream associated with each positive indication determined byblock 136 (FIG. 6). Preferably, the video stream is that produced byexecuting block 134 (FIG. 8) and the portion is stored in the servermemory 46. Preferably, each stored portion is stored so as to maintainits association with each associated positive indication.

Block 144 directs the server processor 44 to cause the system 10 todisplay at least that portion of the video stream associated with eachpositive indication determined by block 136 (FIG. 6). In the secondembodiment, the system 10 is operable to display portions or all of thevideo stream on a user display (not shown), including displayingmultiple portions simultaneously.

Block 146 directs the server processor 44 to perform further imageanalysis on at least that portion of the video stream associated witheach positive indication determined by block 136 (FIG. 6). In variousembodiments, such further image analysis may include objectidentification, object comparison, background elimination, other imageanalysis operations and any combination thereof, for example.

Block 148 directs the server processor 44 to produce a user message inresponse to each positive indication. For example, the system 10 isoperable in the second embodiment to provide a user with an alertmessage for each or for selected instances of indicated motion.

Block 150 directs the server processor 44 to cause the server 40 toproduce a signal for triggering an event. In various embodiments, theserver 40 is operable to communicate such signal such that components ofthe system 10 (not necessarily shown) or other systems are operable totrigger an event. Such events may include any automated response,including a security response.

Block 152 directs the server processor 44 to cause the server 40 toproduce an actuation signal for actuating an external device. Forexample, the server 40 in at least some embodiments is operable toproduce an actuation signal for opening an access door when motion isdetected near the access door. Blocks 146 and 152 may be combined insome embodiments such that motion by a person identified as havingauthorized access may result in access being actuated by the system 10in accordance with the present invention.

While FIG. 9 shows all of blocks 142 to 152 in a specific order, blocks142 to 152 may be performed in any order in response to the usersettings received by executing block 90 (FIG. 6). Any, all or none ofblocks 142 to 152 may be executed in any order in response to the usersettings at a given point in time or processing.

After the appropriate blocks of FIG. 9 are executed in accordance withthe user settings, the method 140 ends and operation control is returnedto the method 88 (FIG. 6) at block 154.

Referring back to FIG. 6, if by executing block 136 the server processor44 determines that there are no positive indications, or after block 138is executed, the method 88 proceeds to block 154.

Block 154 directs the appropriate processing unit of the system 10 todetermine whether there are more images available for analysis. In thesecond embodiment, the server processor 44 is operable to receive asuser input a request to cease image analysis of the method 88 in respectof a given camera 14. In response to such request, the server processor44 is operable to cease processing newly received network packet framesof image data and indications and to transmit a corresponding request tothe given camera 14 to cease obtaining images; and the CPU 20 of thegiven camera 14 is operable to receive such corresponding request, tocease selecting a subsequent first image for image analysis, and tocease capturing images of the plurality of sequential images.Additionally or alternatively, the camera 14 may be operable to ceaseoperation in response to user input received at the camera 14 by the CPU20 directly from the user, for example. In some embodiments, thecontroller device 38 is operable to transmit to a given camera 14 arequest to cease obtaining further images, such that only any remainingimages are processed after which the camera 14 transmits a communicationto the controller device 38 indicating no further images are availablefor analysis. Other arrangements for determining whether there are moreimages available for analysis are possible.

If by block 154 the system 10 determines that there are more images foranalysis, the CPU 20 of the camera 14 is directed to execute blocks 92to 138 again. In embodiments where the reference image is selected as astatic background image, the same static background image may beselected and employed by the camera 14 multiple times for differentexecutions of blocks 92 to 138, for example.

If by block 154 the system 10 determines that there are no more imagesavailable for analysis, the system 10 is directed to end the method 88.

Thus, there is provided a method of analyzing a plurality of imagescaptured by a camera, the method comprising: (a) producing by saidcamera an indication whether a region of an image of said plurality ofimages differs from a corresponding region of a reference image by athreshold extent; (b) transmitting by said camera via a communicationsnetwork to a controller device said indication and image datarepresenting said image; and (c) storing by said controller device saidimage data and said indication in association therewith.

System for Streaming a Video

A system for streaming a video, the video comprising a plurality ofimage frames having associated therewith a source frame rate, each saidimage frame having associated therewith a source pixel resolution, eachsaid image frame comprising a plurality of data packets, includes: (a)receiving means for receiving as user input a viewing area of a viewingwindow, an image region, and a display quality bias; and (b)transmitting means for transmitting a selection of said image framesand, for each said selected image frame, transmitting a data packetselection of said data packets associated only with said image regionand a pixel resolution determined in response to said viewing area, saiddisplay quality bias and said source pixel resolution. The receivingmeans may be operable to receive as user input a chromatic specificationselected from the group consisting of a monochromatic selection and acolour selection. The transmitting means may be operable to transmitmonochrome information only of the video stream when said chromaticspecification is selected as said monochrome selection. The system mayinclude data packet selecting means for selecting said data packetselection. The system may include frame selecting means for selectingsaid selected image frames.

Referring to FIG. 10, the video streaming system is shown generally at154. The video streaming system 154 according to a third embodiment ofthe invention is operable to transmit selected data packets of selectedimage frames of the video stream from the controller device 38, which inthe third embodiment is implemented as the server 40, to one or moreclients 156. In the third embodiment, the selected data packets aretransmitted by the server 40 to one or more clients 156 via a networkswitch 158. The server 40 is operable to obtain the video stream byreceiving the video stream from one or more source devices 12, such asthe cameras 14 (FIG. 1). Additionally or alternatively, the server 40 isoperable in at least some embodiments to transmit selected data packetsretrieved from the server memory 46.

In the third embodiment, the video stream contains any number of imageframes originally generated at a source frame rate, in frames persecond, dependent on the particular originating source of the videostream. For example, a given camera 14 may be operable to produce avideo stream at 30 frames per second, while a different camera 14 may beoperable to produce its video stream at the same or a different framerate. In the third embodiment, the server 40 is operable to determinethe frame rate of a video stream being received from a given camera 14,such as by receiving the frame rate in a communication from the givencamera 14. Additionally or alternatively, the server 40 may be operableto determine a frame rate for a given video stream by analysis of one ormore data packets forming the video stream.

In the third embodiment, each image frame of a given video stream isrepresented by any number of data packets, which typically provide pixelby pixel information for the image frame. Typically, a pixel resolutionrepresents the number of pixels for which such pixel by pixelinformation is provided. For example, a given image frame may containdata packets providing information respecting 307,200 pixels, orapproximately 0.3 Megapixels, arranged as 480 rows of pixels, with eachrow having a width of 640 pixels. A source pixel resolution mayrepresent the pixel resolution of a given video stream as it isgenerated by a given source, such as the camera 14, or retrieved from agiven source, such as being retrieved from the server memory 46, forexample.

The network switch 158 may be implemented or otherwise function in amanner identical, similar, analogous or different to that of the switch30 (FIG. 1) described herein above. In general, the video stream may betransmitted from the server 40 to a given client 156 by any suitabletransmission scheme, communications network, network path or otherconnection, including being transmitted using a link aggregation method.The connection between the server 40 and the client 156 may be referredto as a transmission link.

Each client 156 includes a client processor 160 operable to process thedata packets received from the server 40 and a client memory 162operable to store computer executable instructions for directing theclient processor 160. The client processor 160 may be implemented orotherwise function in a manner identical, similar, analogous ordifferent to that of the server processor 44 (FIG. 1) or the CPU 20(FIG. 1) described herein above. Similarly, the client memory 162 may beimplemented or otherwise function in a manner identical, similar,analogous or different to that of the server memory 46 (FIG. 1) or thememory 22 (FIG. 1) described herein above.

Each client 156 is preferably operable to include or have connectedthereto one or more displays 164 for displaying in a viewing window (notshown) thereof one or more videos processed by the client processor 160.In the third embodiment, the video streaming system 154 is operable toproduce video image data for displaying on colour displays 164,monochrome displays 164 or any combination thereof.

Methods of Streaming a Video

Referring to FIG. 11, the client memory 162 in accordance with the thirdembodiment of the invention contains blocks of code comprising computerexecutable instructions for directing the client processor 160. Also,the server memory 46 in accordance with the third embodiment containsblocks of code comprising computer executable instructions for directingthe server processor 44. Additionally or alternatively, such blocks ofcode may form part of one or more computer program products comprisingcomputer executable instructions embodied in one or more signal bearingmedia, which may be one or more recordable computer-readable media orone or more signal transmission type media, for example.

When electrical power is being supplied to the client processor 160, theclient memory 162, the server processor 44 and the server memory 46, theclient processor 160 and the server processor 44 are directed in thethird embodiment to perform respective steps of a method of the videostreaming system 154 shown generally at 166.

Method 166 begins execution at block 168, which directs at least one ofthe client processor 160 and the server processor 44 to receive userinput in respect of a video stream. In the third embodiment, thenecessary computer executable instruction codes for executing block 168are stored in the client memory 162 for directing the client processor160 to receive the user input. Additionally or alternatively, such codesmay be stored in the server memory 46 for directing the server processor44 to receive the user input. In general, either the server processor 44and/or the client processor 160 may be operable to receive user input.For simplicity of explanation and without limiting the scope of thepresent invention, the description herein that follows will referenceembodiments in which the client processor 160 receives the user input.

Referring to FIG. 12, an exemplary method for implementing steps of themethod 166 (FIG. 11) is shown generally at 170. The method 170 begins atblock 172, which directs the client processor 160 to receive as userinput: (i) a viewing area of a viewing window; (ii) an image region;(iii) a display quality bias parameter; (iv) a chromatic specificationparameter; and (v) a bandwidth limit parameter.

The viewing area typically represents the number of pixels present in agiven viewing window (not shown in the Figures). The viewing area can becalculated as the width in pixels of the viewing window multiplied bythe height in pixels of the viewing window. For example, for a viewingwindow of 640 pixels by 480 pixels, the viewing area is 307,200 pixels,or approximately 0.3 Megapixels. The viewing area may change dynamicallyas a user alters the size of a viewing window on a display 164 (FIG.10), and the system 154 is preferably operable to adapt the videostreaming in response thereto for enhanced transmission efficiency.Generally, the viewing area is constrained within the total viewing areaof the display 164 (FIG. 10).

The image region typically represents a portion of an image frame of thevideo stream. Any coordinate system or scheme suitable for defining aregion of an image frame may be employed. For example, a coordinatesystem for an image frame having a width of 2048 pixels and a height of1536 pixels may define (0,0) as a coordinate for the top-left corner ofthe image frame and (2048, 1536) as a coordinate for the bottom-rightcorner of the image frame. In such exemplary coordinate system, thecoordinates (384,408) and (1664,1128) specify the top-left corner andthe bottom-right corner, respectively, of an image region that iscentered within the image frame and has a width of 1280 pixels and aheight of 720 pixels. A person of ordinary skill in the art willappreciate that an image region may be specified in a variety of waysnot limited to the exemplary coordinate system described herein.

The display quality bias parameter is typically employed to representthe extent to which a user would prefer picture quality resulting from aframe rate (typically measured in frames per second) to be sacrificed toimprove image quality indicated by a pixel resolution (typicallymeasured in Megapixels), or vice versa. The display quality biasparameter may be represented in any suitable manner and include anynumber of selections available to a user. In the third embodiment, thedisplay quality bias parameter is selectable from the group of maximum,high, medium and low quality. However, other selection criteria may beemployed and are within the scope of the present invention.

The chromatic specification parameter typically represents whether ornot to transmit colour information of a video stream, which may beinstead of or in addition to transmitting monochrome information of thevideo stream. In the third embodiment, the data packets representing avideo stream include data packets providing colour information.Transmitting colour information may involve transmitting such datapackets containing the colour information. Transmitting monochromeinformation only may involve transmitting only data packets notcontaining the colour information. Additionally or alternatively,transmitting monochrome information only may involve transmitting onlymonochrome information portions of data packets. In the thirdembodiment, the chromatic specification parameter is selected from thegroup of monochrome selection and colour selection, however otherselection groups may be suitably employed. Typically, only monochromeinformation of the video stream is transmitted if the user has selectedthe monochrome selection of the chromatic specification parameter, andthe colour information is transmitted if the user has selected thecolour selection of the chromatic specification parameter.

The bandwidth limit parameter typically represents a user specifiablelimit of bandwidth usage permitted for the purpose of transmitting oneor more video streams via a given transmission link. The bandwidth limitparameter advantageously permits a user to maintain bandwidth usagewithin a predetermined limit. In the third embodiment, the bandwidthlimit parameter may take any positive numerical value, including aspecification of unlimited bandwidth in which case the system 154 isoperable to not place any limit on bandwidth usage on the basis of thebandwidth limit parameter.

Although FIG. 12 shows an exemplary method in which all of the viewingarea, image region, display quality bias parameter, chromaticspecification parameter and bandwidth limit parameter are received asuser input by executing a single block 172 of code, it is within thescope of the present invention for different forms of user input to bereceived in different manners, including at different times, and bydifferent processes or processors. For example, the system 154 in atleast some embodiments is operable to permit the client processor 160 tocommunicate to the server 40 a request for a list of available videostreams and/or available cameras 14; permit the server 40 to communicateidentifications of one or more available video streams and/or availablecameras 14 possibly in conjunction with other information such as pixelresolution associated with one or more of the identified available videostreams; permit the client processor 160 to receive as user inputrespective viewing areas and image regions in respect of a number ofidentified video streams; and permit the client processor 160 tocommunicate to the server 40 one or more requests to commence streamingidentified video streams. In such embodiments, the system 154 isoperable to receive as user input one or more system 154 parameters,such as the display quality bias, chromatic specification and bandwidthlimit parameters, at any time prior to or subsequent to communicatingsuch requests to commence streaming. The system 154 in at least someembodiments is operable to receive and store different parameter valuesin respect of different identifiable video streams, including receivingand/or storing different parameter values at different times. The system154 in at least some embodiments is operable to assign a default valueto any one or more system 154 parameters, and to receive user input foroverriding a system 154 default value. A default value for the bandwidthlimit parameter may be unlimited bandwidth, for example. In variousembodiments, received user input may be stored in the client memory 162,the server memory 46, or any combination thereof for example.

Still referring to FIG. 12, after block 172 has been executed, themethod 170 ends and control is returned to the method 166 at block 174(FIG. 11).

Referring back to FIG. 11, block 174 directs the server processor 44 totransmit a selection of image frames selected in accordance with theuser input, such as may have been received by block 172 (FIG. 12), andto transmit, for each selected image frame, a data packet selection ofdata packets thereof selected in accordance with the user input.

Referring to FIG. 13, an exemplary method for executing steps of block174 (FIG. 11) is shown generally at 176. The method 176 begins at block178, which directs a suitable processor to determine permitted pixelresolutions equal to the source pixel resolution divided by the resultof four raised to an integer power. In the third embodiment, suchsuitable processor is the client processor 160. Additionally oralternatively, the server processor 44 may perform operations directedby block 178 for example.

In the third embodiment, one or more values of permitted pixelresolutions associated with a given video stream may be determinedaccording to the formula:

where

-   -   IR_(p)□        are the permitted pixel resolutions, and    -   IR_(a) is the source pixel resolution of the given video stream.

For example, if the source pixel resolution is 4 Megapixels (MP), thepermitted pixel resolutions are { . . . 64 MP, 16 MP, 4 MP, 1 MP, 0.25MP . . . }. In embodiments of the invention, a plurality of permittedpixel resolutions need not be specifically computed. In suchembodiments, only one particular permitted pixel resolution may bedetermined for example.

Block 180 in the third embodiment directs the client processor 160 toselect a particular permitted pixel resolution, from among the permittedpixel resolutions, that is: (i) closest to and greater than or equal tothe viewing area (which particular permitted pixel resolution may bereferred to as a maximum quality pixel resolution) if the displayquality bias parameter is selected as maximum quality; (ii) equal to onefourth of the maximum quality pixel resolution if the display qualitybias parameter is selected as high quality; (iii) equal to one sixteenthof the maximum quality pixel resolution if the display quality biasparameter is selected as medium quality; and (iv) equal to onesixty-fourth of the maximum quality pixel resolution if the displayquality bias parameter is selected as low quality. In at least someembodiments, blocks 178 and 180 may not be separately executed and avalue of the integer power referenced by block 178 and corresponding tothe particular permitted pixel resolution of block 180 may be determinedin accordance with a single block of code.

A particular permitted pixel resolution may be selected by selecting thevalue of n such that the formula for the permitted pixel resolutions issatisfied in accordance with the viewing area and the display qualitybias parameter. By way of a first example, if the viewing area is 0.4 MPand the source pixel resolution is 4 MP, then the particular permittedpixel resolution corresponding to each of maximum, high, medium and lowdisplay quality is 1 MP, 0.25 MP, 0.0625 MP and 0.015625 MP,respectively. By way of a second example, if the viewing area is 5.2 MPand the source pixel resolution is 4 MP, then the particular permittedpixel resolution corresponding to each of maximum, high, medium and lowdisplay quality is 16 MP, 4 MP, 1 MP and 0.25 MP, respectively.

After block 180 has been executed, block 182 directs the clientprocessor 160 to assign a pixel resolution to the lesser of theparticular permitted pixel resolution and the source pixel resolution.For example, if the source pixel resolution is 4 MP and the particularpermitted pixel resolution is 1 MP, then the pixel resolution isassigned the value of 1 MP, whereas if the source pixel resolution is 4MP and the particular permitted pixel resolution is 16 MP, then thepixel resolution is assigned the value of 4 MP. Block 180 advantageouslyfacilitates the system 154 in not attempting to transmit more pixelinformation than is available from a given source.

Although not shown in FIG. 13, block 182 in at least some embodimentsalso directs the client processor 160 to communicate the value of thepixel resolution from the client 156 to the server 40. After block 182has been executed, block 184 is executed as shown in FIG. 14.

Referring to FIG. 14, block 184 in accordance with the third embodimentdirects the client processor 160 to determine a stream bandwidth limitequal to the bandwidth limit parameter divided by a number of videostreams. In embodiments where a given client 156 is operable to receivefrom the server 40 a plurality of video streams, the stream bandwidthlimit is determined in accordance with the number of video streamscurrently being received, expected to be received, requested to bereceived, or expected to be requested to be received, for example, bythe given client 156. In variations, any suitable weighting orprioritization scheme may be employed to allocate bandwidth for use withdifferent video streams and to determine a stream bandwidth limit foreach such video stream. A weighting or prioritization for a given videostream may be determined in accordance with user input, for example. Thesame stream bandwidth limit being employed in respect of a plurality ofvideo streams, a unique stream bandwidth limit being employed for eachvideo stream, and any combination thereof is within the scopecontemplated by the present invention. Although not shown in FIG. 14,block 184 in at least some embodiments also directs the client processor160 to communicate the value of the stream bandwidth limit from theclient 156 to the server 40.

While blocks 178 to 184 are described herein above as directing theclient processor 160, it is within the scope of the present inventionfor such blocks to direct the server processor 44. In embodiments whereone or more of blocks 178 to 184 direct the server processor 44, theserver 40 is preferably operable to receive user input from a user, fromone or more clients 156, or both from a user and one or more clients156.

Block 186 in accordance with the third embodiment directs the serverprocessor 44 to select data packets of a first image frame of a givenvideo stream such that the selected data packets are associated onlywith the image region, monochrome information if the chromaticspecification parameter is set to the monochrome selection, and thepixel resolution (such as that determined by block 182). Executing block186 advantageously enhances transmission efficiency by not selectingdata packets for transmission from the server 40 to the client 156 thatthe client 156 has indicated will not be displayed. In some embodiments,portions of data packets are not transmitted in accordance withindications received from the client 156. In a variation, block 186directs the server processor 44 to select data packets, or portionsthereof, of the first image frame such that the selected data packetsare associated only with the image region and the pixel resolution,without regard to any chromatic specification.

In some embodiments, block 186 directs the server processor 44 todetermine the compression of the first image frame of the given videostream; compare the compression to a minimum permitted compression; and,if the compression is less than the minimum permitted compression,adjust the compression of the first image frame such that thecompression becomes equal to or greater than the minimum permittedcompression. Determining the compression of a given image frame mayinvolve determining the number of data bits used to digitally representeach pixel of the given image frame. Adjusting the compression of agiven image frame may involve reducing the number of bits per pixel ofthe given image frame. Additionally or alternatively, adjusting thecompression of the given image frame may involve increasing the numberof bits per pixel of the given image frame. The minimum permittedcompression may be a system 154 parameter, including possibly being auser specifiable parameter for example. The system 154 may include auser specifiable parameter for enabling and disabling the system 154feature of determining and possibly altering the compression of imageframes of a given video stream.

Block 188 in the third embodiment directs the server processor 44 todetermine a frame size of the selected data packets. In general, framesize typically represents the number of bytes of data associated with agiven frame. In the third embodiment, the frame size of the selecteddata packets selected by block 186 in respect of the first image frameadvantageously provides an indication of the amount of data constitutedby the first image frame. In variations, block 188 may direct the serverprocessor 44 to determine an average frame size of data packets selectedin accordance with block 186 in respect of a plurality of image frames,thereby advantageously reducing an error margin of the frame size.

Block 190 in the third embodiment directs the server processor 44 todetermine a frame rate limit equal to the stream bandwidth limit (suchas that determined by block 184) divided by the frame size (such as thatdetermined by block 188). In embodiments and circumstances in which thestream bandwidth limit is indicative of an unlimited bandwidth (forexample, by no finite bandwidth limit having been set by the user), theframe rate limit may be assigned a representation of an infinite valueor other indication that no finite frame rate limit is being set.

In some embodiments, block 190 directs the server processor 44 todetermine whether the frame rate limit is less than a minimum permittedframe rate limit and, if so, adjust the frame size such that the framerate limit becomes equal to or greater than the minimum permitted framerate limit. Adjusting the frame size may involve reducing the frame sizeby increasing the compression associated with the selected data packets.Additionally or alternatively, adjusting the frame size may involveincreasing the frame size by reducing the compression associated withthe selected data packets, for example. Changing the compression mayinvolve changing the selection of data packets, decompressing datapackets and re-compressing the data packets at a new compression rate,applying a compression change algorithm to the selected data packets, orany combination thereof for example. The minimum permitted frame ratelimit may be a system 154 parameter, including possibly being a userspecifiable parameter for example. The system 154 may include a userspecifiable parameter for enabling and disabling the system 154 featureof comparing the frame rate limit to the minimum permitted frame ratelimit and possibly altering the compression of image frames of a givenvideo stream accordingly.

Block 192 in the third embodiment directs the server processor 44 todetermine whether the frame rate limit is greater than or equal to thesource frame rate.

If the frame rate limit is greater than or equal to the source framerate, block 194 directs the server 44 to transmit selected data packetsof the image frames of the video stream. In the third embodiment, suchdata packets for each image frame are selected in a manner substantiallysimilar to the selection of data packets of the first image frame inaccordance with block 186. In accordance with block 194, the selecteddata packets of all image frames of the video stream are transmitted.

If the frame rate limit is less than the source frame rate, block 196directs the server processor 44 to transmit selected data packets of asubset of the image frames of the video stream such that thetransmission rate of the selected image frames is less than or equal tothe frame rate limit. (For each image frame, such data packets may beselected for transmission in a manner substantially similar to theselection of data packets of the first image frame in accordance withblock 186.) The image frames of the subset are preferably selected fortransmission such that the transmission rate at which the selected imageframes are transmitted is equal to or approximately equal to, but nogreater than, the frame rate limit. For example, if the source framerate is 30 frames per second, and the frame rate limit is calculated as7.6 frames per second, then transmitting 7 image frames for every 30image frames of the video stream will result in a transmission rate thatis less than or equal to the frame rate limit. Similarly, transmitting15 image frames for every 60 image frames of the video stream will alsoresult in a transmission rate that is less than or equal to the framerate limit. A person of ordinary skill in the art will appreciate thatnumerous selections of image frames of the subset may result in atransmission rate less than or equal to the frame rate limit.

Executing block 196 advantageously enhances transmission efficiency bynot transmitting image frames from the server 40 to the client 156 thatthe client 156 has indicated will not be displayed.

In the third embodiment, the server processor 44 is preferably operableto select the subset so as to produce a substantially uniform temporaldistribution of the selected image frames. For example, 7 of every 30image frames may be transmitted by repeating the pattern of transmittingevery fourth image frame for five such transmissions followed bytransmitting every fifth image frame for two such transmissions.

After executing block 194 or block 196, the method 176 ends and theprocess returns to the method 166 (FIG. 11), which also ends.

While not shown in the Figures, the system 154 is in at least someembodiments operable to iteratively execute methods of streaming a videodescribed herein for multiple video streams in respect of multipleclients 156, multiple servers 44, multiple sources such as the cameras14, and any combination thereof.

While not shown in the Figures, the system 154 is preferably operable toiterate one or more steps of the method 166 such that one or morequantities, such as the stream bandwidth limit, are adjusted in responseto the client 156 receiving data packets. In exemplary circumstanceswhere the client 156 is not rendering all received data packets fordisplay due to processing speed limitations, for example, the client 156may be operable to adjust the stream bandwidth limit, including possiblytransmitting a new value of the stream bandwidth limit to the server 44.The server 44 in at least some embodiments is operable to perform aredetermination of the frame rate limit, thereby adapting thetransmission frame rate of the selected image frames for continuouslyadaptable transmission efficiency.

Furthermore, the system 154 is in at least some embodiments operable toreceive subsequent user input and to cause redeterminations of theselection of data packets, the selection and/or compression of imageframes, the selection of the video stream, and any combination thereoffor example.

Thus, there is provided a method of streaming a video, the videocomprising a plurality of image frames having associated therewith asource frame rate, each said image frame having associated therewith asource pixel resolution, each said image frame comprising a plurality ofdata packets, the method comprising: (a) receiving as user input aviewing area of a viewing window, an image region, and a display qualitybias; and (b) transmitting a selection of said image frames and, foreach said selected image frame, transmitting a data packet selection ofsaid data packets associated only with said image region and a pixelresolution determined in response to said viewing area, said displayquality bias and said source pixel resolution.

While embodiments of the invention have been described and illustrated,such embodiments should be considered illustrative of the inventiononly. The invention may include variants not described or illustratedherein in detail. For example, an image captured by a given camera maybe selected by the user, or by the server processor in accordance withuser settings, for use by the given camera as its reference image. Thus,the embodiments described and illustrated herein should not beconsidered to limit the invention as construed in accordance with theaccompanying claims.

1. A method of streaming a video, the video comprising a plurality ofimage frames having associated therewith a source frame rate, each saidimage frame having associated therewith a source pixel resolution, eachsaid image frame comprising a plurality of data packets, the methodcomprising: (a) receiving as user input a viewing area of a viewingwindow, an image region, and a display quality bias; and (b)transmitting a selection of said image frames and, for each saidselected image frame, transmitting a data packet selection of said datapackets associated only with said image region and a pixel resolutiondetermined in response to said viewing area, said display quality biasand said source pixel resolution.
 2. The method of claim 1 wherein step(a) further comprises receiving as user input a chromatic specificationselected from the group consisting of a monochromatic selection and acolour selection, and wherein step (b) comprises transmitting onlymonochrome information of the video stream if said chromaticspecification is selected as said monochrome selection.
 3. The method ofclaim 1 wherein step (a) comprises receiving as user input said displayquality bias selected from the group consisting of: a maximum quality, ahigh quality, a medium quality and a low quality, wherein step (b)comprises determining a permitted pixel resolution equal to said sourcepixel resolution divided by the result of four raised to an integerpower, and determining said integer power such that said permitted pixelresolution is equal to a particular said permitted pixel resolutionclosest to and greater than or equal to said viewing area if saiddisplay quality bias is selected as said maximum quality, equal to onefourth of said particular permitted pixel resolution if said displayquality bias is selected as said high quality, equal to one sixteenth ofsaid particular permitted pixel resolution if said display quality biasis selected as said medium quality and equal to one sixty-fourth of saidparticular permitted pixel resolution if said display quality bias isselected as said low quality, and wherein the method further comprisesassigning said pixel resolution to the lesser of said permitted pixelresolution and said source pixel resolution.
 4. The method of claim 1wherein step (b) comprises adjusting a compression of said image framessuch that said compression is equal to or greater than a minimumcompression.
 5. The method of claim 1 wherein step (b) comprisesselecting said selection of said image frames such that a streambandwidth limit is not exceeded.
 6. The method of claim 5 whereinselecting said selection of said image frames such that a streambandwidth limit is not exceeded comprises receiving as user input abandwidth limit associated with a transmission link, and setting saidstream bandwidth limit equal to said bandwidth limit divided by a numberof said videos being transmitted via said transmission link.
 7. Themethod of claim 5 wherein selecting said selection of said image framessuch that a stream bandwidth limit is not exceeded comprises determininga frame size of said data packet selection, determining a frame ratelimit equal to said stream bandwidth limit divided by said frame size,selecting said image frames if said frame rate limit is greater than orequal to said source frame rate, and, if said frame rate limit is lessthan said source frame rate, selecting a subset of said image framessuch that a transmission rate of said subset is less than or equal tosaid frame rate limit.
 8. The method of claim 7 wherein determining aframe rate limit equal to said stream bandwidth limit divided by saidframe size comprises adjusting said frame size such that said frame ratelimit is equal to or greater than a minimum frame rate limit.
 9. Themethod of claim 7 comprising selecting said subset so as to produce asubstantially uniform temporal distribution of said selected imageframes.
 10. The method of claim 7 wherein determining a frame size ofsaid data packet selection comprises determining an average frame sizeassociated with a plurality of said selected image frames.
 11. A systemfor streaming a video, the video comprising a plurality of image frameshaving associated therewith a source frame rate, each said image framehaving associated therewith a source pixel resolution, each said imageframe comprising a plurality of data packets, the system comprising: (a)a client operable to receive as user input a viewing area of a viewingwindow, an image region, and a display quality bias; and (b) acontroller device operable to transmit a selection of said image framesto said client and, for each said selected image frame, transmitting adata packet selection of said data packets associated only with saidimage region and a pixel resolution determined in response to saidviewing area, said display quality bias and said source pixelresolution.
 12. The system of claim 11 wherein said client is operableto receive as user input a chromatic specification selected from thegroup consisting of a monochromatic selection and a colour selection,and wherein said controller device is operable to transmit monochromeinformation only of the video stream when said chromatic specificationis selected as said monochrome selection.
 13. The system of claim 11wherein said client is operable to receive as user input said displayquality bias selected from the group consisting of: a maximum quality, ahigh quality, a medium quality and a low quality, wherein said client isoperable to determine a permitted pixel resolution equal to said sourcepixel resolution divided by the result of four raised to an integerpower, said client is operable to determine said integer power such thatsaid permitted pixel resolution is equal to a particular said permittedpixel resolution closest to and greater than or equal to said viewingarea if said display quality bias is selected as said maximum quality,equal to one fourth of said particular permitted pixel resolution ifsaid display quality bias is selected as said high quality, equal to onesixteenth of said particular permitted pixel resolution if said displayquality bias is selected as said medium quality and equal to onesixty-fourth of said particular permitted pixel resolution if saiddisplay quality bias is selected as said low quality, said client isoperable to assign said pixel resolution to the lesser of said permittedpixel resolution and said source pixel resolution, and wherein saidclient is operable to communicate to said controller device said pixelresolution.
 14. The system of claim 11 wherein said controller device isoperable to adjust a compression of said image frames such that saidcompression is equal to or greater than a minimum compression.
 15. Thesystem of claim 11 wherein said controller device is operable to selectsaid selection of said image frames such that a stream bandwidth limitis not exceeded.
 16. The system of claim 15 wherein said client isoperable to receive as user input a bandwidth limit associated with atransmission link, operable to set said stream bandwidth limit equal tosaid bandwidth limit divided by a number of said videos being receivedby said client via said transmission link, and operable to communicateto said controller device said stream bandwidth limit.
 17. The system ofclaim 15 wherein said controller device is operable to determine a framesize of said data packet selection, determine a frame rate limit equalto said stream bandwidth limit divided by said frame size, select saidimage frames if said frame rate limit is greater than or equal to saidsource frame rate, and, if said frame rate limit is less than saidsource frame rate, select a subset of said image frames such that atransmission rate of said subset is less than or equal to said framerate limit.
 18. The system of claim 17 wherein said controller isoperable to adjust said frame size such that said frame rate limit isequal to or greater than a minimum frame rate limit.
 19. The system ofclaim 17 wherein said controller device is operable to select saidsubset so as to produce a substantially uniform temporal distribution ofsaid selected image frames.
 20. The system of claim 17 wherein saidcontroller device is operable to determine an average frame sizeassociated with a plurality of said selected image frames.
 21. A systemfor streaming a video, the video comprising a plurality of image frameshaving associated therewith a source frame rate, each said image framehaving associated therewith a source pixel resolution, each said imageframe comprising a plurality of data packets, the system comprising: (a)receiving means for receiving as user input a viewing area of a viewingwindow, an image region, and a display quality bias; and (b)transmitting means for transmitting a selection of said image framesand, for each said selected image frame, transmitting a data packetselection of said data packets associated only with said image regionand a pixel resolution determined in response to said viewing area, saiddisplay quality bias and said source pixel resolution.
 22. The system ofclaim 21 wherein said receiving means is operable to receive as userinput a chromatic specification selected from the group consisting of amonochromatic selection and a colour selection, and wherein saidtransmitting means is operable to transmit monochrome information onlyof the video stream when said chromatic specification is selected assaid monochrome selection.
 23. The system of claim 21 comprising datapacket selecting means for selecting said data packet selection.
 24. Thesystem of claim 21 comprising frame selecting means for selecting saidselected image frames.
 25. The system of claim 23 comprising frameselecting means for selecting said selected image frames.